Serious players don't want off brand or flat used tennis balls, sorry I can't picture one being able to grow such retail sales by much. Most players have established suppliers like their local sports shop.
If you have new, recognizable brand name products you might try setting up a store on Amazon, which lends you more credibility than Craigslist.
To find out the best advertisement company for advertising that. And choose what type of advertisement is best for this. The advertisement must be favorable for your convenient and know the people
I would suggest you to advertise your product in eCommerce web sites which are popular in market like ebay, amazon are many that will help you in better advertising.
post professional flyers near the parks. go from park to park wherever you can.
I have tennis balls and the only ad I've ever had for them is on craigslist. I sell them for a really good price and i wanna get myself out there so i can sell more. Help?
